I've tried it, but not all the properties has changes (e.g. the cursor bar colors didn't change...I don't know why).
However, doing so I should pass object-by-object with the format painter for every sheet of every document, so it takes me a long time to do.
I'd like to know if there is the possibility of change all object a-time, by setting the document's property (so I should make the changes only once for document).
Q1: Document Properties->Caption sets default values for all objects created subsequently.
You can use themes to change colors globally. See Object Properties->Layout for "Theme Maker" and "Apply Theme" buttons.
Q2: With "tag", do you mean "tab" of a worksheet? In that case you can change the tab color for a single sheet in Sheet->Properties->General->Tab settings, and propagate those new colors to every other sheet by clicking the "Apply to All" button.
Very good for the answer to Q2 :-)
I tried to make as you suggest for the Q1 and I create a Theme ad hoc with the characteristics that I'd like to set, but when I apply it on another document, only the sheet background and the tag setting are replaced; the active/inactive header color setting, the border color setting and the cursor bar color setting are not replaced.
Note that in the color theme wizard I specify all the properties to be included on the theme.